Chest Freezer and Controlling Temperature

[arnobg]

I just picked up a 7 cu ft chest freezer from Craigslist to ferment in the summer, in the winter ambient garage temperature is cool enough. I have been reading about the STC 1000 but am not sure when would the heat part be used? Do most people use this and is it necessary in the summer when you are just trying to cool?

 

[Sammy86]

I just picked up a 7 cu ft chest freezer from Craigslist to ferment in the summer, in the winter ambient garage temperature is cool enough. I have been reading about the STC 1000 but am not sure when would the heat part be used? Do most people use this and is it necessary in the summer when you are just trying to cool?

I use a Johnson temp controller instead of the STC mainly because I'm not handy enough to wire it. I have my kegerator/ferm chamber in my basement which stays cool during the summer and even cooler in the winter at no point have I needed to heat up my wort to hold temp.

The heating is not entirely necessary IMO but it is nice to have.

 

[day_trippr]

I just picked up a 7 cu ft chest freezer from Craigslist to ferment in the summer, in the winter ambient garage temperature is cool enough. I have been reading about the STC 1000 but am not sure when would the heat part be used? Do most people use this and is it necessary in the summer when you are just trying to cool?

In my case, my humble brewery experiences temps below the ideal fermentation temperature for most ale yeasts in the cooler seasons, so a small heater is required. During the warm seasons the heater is not needed.

A dual stage controller makes this easy - it will automagically use the heater when needed...

Cheers!

 

[BowAholic]

My 27 cf chest freezer/ferment chamber is in an outdoor shed. I use a small (7 watt) space heater in the winter to maintain temps inside the chamber. Seems like the heat side is the only side used during the colder part of winter.

 

[noggins]

you could possibly get away without a heater, depending on what your ambient temp is in winter. I'm still getting used to the settings on my stc1000, you can set target temp, range, and cycle time(whatever that is?). I've actually caught it about 5 degrees colder than I thought it should go based on my settings, in which case a heater would've been nice(I just opened the lid for a minute and that did it). So basically, once you figure out all the settings you'll probably be fine.

If not, use some type of aquarium heater or light or hair dryer or heating pad or whatever. Here's what I'm planning on buying this december/january when it gets in the 50's: http://www.amazon.com/dp/B0002AQCPK/?tag=skimlinks_replacement-20

 

[arnobg]

Thanks for the tips, I'll ride it out and see how it works without a heater. Wasn't sure if this was a "required" part of the setup but makes sense now.

 

[kombat]

I used to just use the "cooling" part of my STC-1000, but I'd occasionally find the temperature considerably lower than the target. So I added a 100W light bulb under a coffee can and plugged it into the "Heat" circuit. Then I found I got wild temperature fluctuations. Since the volume of the beer is relatively large, it took quite a while for the beer to warm back up. I'd lift the lid to the freezer and it was like an oven in there. By the time the beer warmed back up, the freezer was so hot that the beer kept rising well above the target, and the freezer eventually kicked back in, first trying to remove all that extra heat, then trying to cool the beer back down. I ruined a batch of Kolsch this way, the temperature swung by up to 4° C in both directions!

I replaced the light bulb with a heating belt, and now my temperature stays within 0.3° C of the target constantly, I get much more consistent ferments.

 

[Gavin C]

I just picked up a 7 cu ft chest freezer from Craigslist to ferment in the summer, in the winter ambient garage temperature is cool enough. I have been reading about the STC 1000 but am not sure when would the heat part be used? Do most people use this and is it necessary in the summer when you are just trying to cool?

I use a 7.1cu ft chest freezer also. It is in a climate controlled room. In north Texas adding heat to the chamber is not needed for most of the year. if I want to ramp up the temperatures I just let it passively rise. Once it reaches the desired set point that's where it will be kept by the freezer.

I add in a small heater during the cooler times of the year but even then it is rarely needed as again the ambient of the unheated room in which the freezer sits would rarely get much below 65F unless I was away and the heating was off.

Fermentation chamber with STC1000 (very easy DIY)


Heater


If using this type of heater don't point it right at the fermenter if you can avoid it. Can cause a hot spot

 

[dunbruha]

I use a 7.1cu ft chest freezer also. It is in a climate controlled room. In north Texas adding heat to the chamber is not needed for most of the year. if I want to ramp up the temperatures I just let it passively rise. Once it reaches the desired set point that's where it will be kept by the freezer.

I add in a small heater during the cooler times of the year but even then it is rarely needed as again the ambient of the unheated room in which the freezer sits would rarely get much below 65F unless I was away and the heating was off.

Where do you locate your temp probe? Is it on the outside of the FV?

 

[Gavin C]

Where do you locate your temp probe? Is it on the outside of the FV?

Yes. On the outside of the FV measuring beer temp. Insulated from the air temp in the freezer.

Hysteresis at +/- 0.3 C delay at 10 mins. STC1000

 

[dunbruha]

Yes. On the outside of the FV measuring beer temp. Insulated from the air temp in the freezer.

Hysteresis at +/- 0.3 C delay at 10 mins. STC1000

Thanks. I am trying out a thermowell, but am getting some large temp swings. I have the Inkbird, with similar settings as your STC.

Have you ever tried putting the probe in a small container of water somewhere in the chamber?

 

[Gavin C]

Thanks. I am trying out a thermowell, but am getting some large temp swings. I have the Inkbird, with similar settings as your STC.

Have you ever tried putting the probe in a small container of water somewhere in the chamber?

No, as I am only concerned with the temperature of the fermenting beer. It's an exothermic process so monitoring ambient temps largely defeats the purpose. I won't have any control over or measure of the beer temp.


I do measure ambient in this way in my kegerator. Probe sits in a small (4oz) bottle of baking soda. No exothermic process at work so everything will reach equilibrium.

 

[dunbruha]

No, as I am only concerned with the temperature of the fermenting beer. It's an exothermic process so monitoring ambient temps largely defeats the purpose. I won't have any control over or measure of the beer temp.

I guess I will go back to the probe on the outside of the FV (I have a 1/4 bbl Sanke). I just got the Sanke fermentation conversion kit from BrewHardware, and was hoping that the thermowell would give me a better measure of the internal temp. I have a second Inkbird (the probe is taped to the outside of the Sanke), and the difference in temperatures between the inside and outside is sometimes as much as 15*F. If the outside gets a little too cold, I'm not too worried, but I have a heater in there, and if it is running long to get the insides up to temp, then the outside might get too hot.

 

[Gavin C]

I guess I will go back to the probe on the outside of the FV (I have a 1/4 bbl Sanke). I just got the Sanke fermentation conversion kit from BrewHardware, and was hoping that the thermowell would give me a better measure of the internal temp. I have a second Inkbird (the probe is taped to the outside of the Sanke), and the difference in temperatures between the inside and outside is sometimes as much as 15*F. If the outside gets a little too cold, I'm not too worried, but I have a heater in there, and if it is running long to get the insides up to temp, then the outside might get too hot.

Those look like a great product for converting the kegs to FV's.

 

[dunbruha]

Those look like a great product for converting the kegs to FV's.

It is a good product, but I am disappointed that the thermowell measurements cause such a temp swing. I guess I need to save up for a BrewPi or STC-1000+ ...

 

[day_trippr]

[...]I have a second Inkbird (the probe is taped to the outside of the Sanke), and the difference in temperatures between the inside and outside is sometimes as much as 15*F. [...]

Is the probe simply taped to the Sanke and not insulated at all?
If so, it's hardly surprising that probe sees rather wild swings while the thermowell'd probe is barely budging. It's in a chest freezer, after all, which is designed to be able to take the whole cabinet well below 0°F...

Cheers!

 

[Gavin C]

Some sort of insulation is needed if you're not already using some.

Insulated probe on outside of FV. Active fermentation, temps are stable at 10C.

 

[dunbruha]

Is the probe simply taped to the Sanke and not insulated at all?
If so, it's hardly surprising that probe sees rather wild swings while the thermowell'd probe is barely budging. It's in a chest freezer, after all, which is designed to be able to take the whole cabinet well below 0°F...

Cheers!

I use a sponge (held in place with a Velcro strap), which holds the probe tight to the Sanke.

 

[day_trippr]

I use a sponge (held in place with a Velcro strap), which holds the probe tight to the Sanke.

Use something that's actually an insulator...

Cheers!

 

[dunbruha]

Use something that's actually an insulator...

Cheers!

I don't see the difference between a (dry) sponge and bubble wrap (which many people use). It is full of air pockets, just like foam.

 

[day_trippr]

I agree that bubble wrap is weak sauce and wouldn't recommend using it.
Try using inch thick closed cell foam...

Cheers!

 

[dunbruha]

I agree that bubble wrap is weak sauce and wouldn't recommend using it.
Try using inch thick closed cell foam...

Cheers!

I could try it, but I am not familiar with it. Any suggestions for places to buy it?

 

[day_trippr]

No idea where to buy it. I scavenged what I have (white, inch thick, flexible) from shipping cartons (window A/C unit came in a box with a crapton of it)...

Cheers!

 

[dunbruha]

No idea where to buy it. I scavenged what I have (white, inch thick, flexible) from shipping cartons (window A/C unit came in a box with a crapton of it)...

Cheers!

Hmmm, OK, I'll keep my eyes open.

 

[day_trippr]

fwiw, this is a temperature log from my keezer controller.
It shows room temperature, tower air temperature, the interior temperature just below the lid liner, the interior temperature just above the floor, and the temperature of one of the six or seven kegs that are on board.



In addition to the 40mm tower cooler, there is a 120mm "stirring" fan which is why the upper and lower temperatures track so closely.

The thing to notice is how little coupling there is on the keg temperature plot to the ~15°F swings in the interior, "ambient" temperature. I attribute this to a healthy insulator above a reasonably-well coupled probe. Rather than seeing spikes as the compressor cycles, there's a nice smooth slope up and down inside the allowed 2°F window, behavior any decent controller should manage easily. ...

Cheers!

 

[Gavin C]

Great Data documentation

Brilliant. From what bits and pieces I've seen of your keezer, I am extremely envious.

Wonderful demonstration of the rationale behind monitoring keg temp in a well filled keezer with good air circulation.

Thanks for sharing that.

 

[dunbruha]

The thing to notice is how little coupling there is on the keg temperature plot to the ~15°F swings in the interior, "ambient" temperature. I attribute this to a healthy insulator above a reasonably-well coupled probe. Rather than seeing spikes as the compressor cycles, there's a nice smooth slope up and down inside the allowed 2°F window, behavior any decent controller should manage easily. ...

Cheers!

Very nice! Have you ever measured the temperature at the center of the FV (with a thermowell)?

What kind of controller do you have? It must have multiple probe inputs!

 

[day_trippr]

The control is done by BrewPi running on the same RaspberryPi that runs my RaspberryPints tap list and my temperature logger (the latter is where that plot comes from). That's three HBT threads (at least) right there

Anyway, I've never attempted to use a thermowell in my keezer. The level of complication vs questionable benefit: I'd have to either modify all 14 keg lids with 'wells, or swap lids around, for at best a half-degree of precision. Either way, not gonna happen.

I also use BrewPi to manage a couple of ferm chambers, and use the same well-insulated/strapped-to-the carboy technique. It's simpler than dealing with thermowells, and let's face it, a half-degree is background noise in The Big Picture...

Cheers!

 

[kombat]

Thanks. I am trying out a thermowell, but am getting some large temp swings.

I had the same thing when I was using a light bulb in a paint can as the heater. Ruined a batch of Kolsch because the temperature of the beer was all over the place.

Now I use a heating belt around the carboy to provide the "heat" element during fermentation, and my temperatures are MUCH more stable.

 

[Collmorgen]

I use a ceramic reptile heater bulb that screws in a standard light fixture. I think that it's a 70W.

 

[dunbruha]

I had the same thing when I was using a light bulb in a paint can as the heater. Ruined a batch of Kolsch because the temperature of the beer was all over the place.

Now I use a heating belt around the carboy to provide the "heat" element during fermentation, and my temperatures are MUCH more stable.

Are you using a thermowell, or are you attaching the probe to the outside of the FV?

I used to used a reptile heater, but it started to melt the top of my freezer. Now I use a heating pad (http://www.homebrewing.org/Heat-Pad-for-Beer-and-Wine-Making_p_2509.html) underneath the FV.

 

[kombat]

Are you using a thermowell, or are you attaching the probe to the outside of the FV?

I use a thermowell. I have my glass carboy sitting in a chest freezer, with one of those blue heating belts around the carboy about 1/3 of the way up from its bottom. I have a thermowell stopper with an S-airlock (because the air inside the carboy contracts, creating a vacuum during cooling cycles when fermentation is not vigorous). I have the freezer plugged into the "cool" plug of an STC-1000, and the heating belt plugged into "heat." For US-05 (my usual yeast), I have the STC-1000 set to 63.5° F, +/- 0.5° F, and with this setup, the temperature stays VERY close to tolerance. As in, never higher than 64.5 and never lower than 62.5.

 

[dunbruha]

I use a thermowell. I have my glass carboy sitting in a chest freezer, with one of those blue heating belts around the carboy about 1/3 of the way up from its bottom. I have a thermowell stopper with an S-airlock (because the air inside the carboy contracts, creating a vacuum during cooling cycles when fermentation is not vigorous). I have the freezer plugged into the "cool" plug of an STC-1000, and the heating belt plugged into "heat." For US-05 (my usual yeast), I have the STC-1000 set to 63.5° F, +/- 0.5° F, and with this setup, the temperature stays VERY close to tolerance. As in, never higher than 64.5 and never lower than 62.5.

Wow, that's really good. I have pretty much the same setup as you, except I have a 1/4 bbl Sanke as my FV, and I have a heating pad at the bottom of the keg. I seem to be getting a lot of temp swings, but I only have a few batches with this system. I'm brewing another this Saturday, and I think I'll try putting the probe on the outside. If that doesn't help, I may try the heating belt.

 

[frettfreak]

I have a stainless bevair freezer for my chamber. I have the freezer plugged into the cool side of my homemade STC1000 box and during the winter months i use a ceramic reptile heater to heat the entire thing.

I have my temp probe wrapped with dome bubble wrap on one side and tape it to the FV of the newest beer.

Is heating absolutely necessary? No, but neither is a freezer. Stable temps are the key to getting the most out of your wort and yeast, not just keeping it cool enough. With this setup i do allow it to drift 0.5 degree in either direction.

 

[beernutz]

The heat part is necessary if you are brewing a Saison using Wyeast 3724 yeast which likes 90 degrees to fully attenuate without a stall.

I have my fermentation chest freezer in my garage storage room and during our few weeks of "winter" when the night time temp falls into the 30s I use a small hair dryer to heat it. I rarely use both the heat and cold outlets on my STC-1000 at the same time. By that I mean if ambient air temp is low or if I want to brew something like a Saison I just plug in the hair dryer to the "hot" outlet but nothing in the "cold" outlet.

Under normal circumstances here the ambient temp is higher than what I'm fermenting at so I just keep the freezer cord plugged into the cold outlet of the STC-1000.